<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			test(1);
			
			function test(n){
				document.write(n+"<br>");
				n++;
				if(n<=3){
					test(n);
				}
				document.write(n+"<br />");
			}
			
		</script>
	</body>
</html>
